(x cookies) / (23 students - (12/2) students) = 2 cookies per student
[x / (23 - 6)] cookies per student = 2 cookies per student
23 students * (2 cookies per students) - 12 cookies = x cookies
The "students" unit cancels
46 cookies - 12 cookies = x cookies
x cookies = 34 cookies
We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
The greatest common factor (gcf) is 6.
Answer:
B) 42:28
Step-by-step explanation:
First, let's get 12:18 simplified to make it easier to compare:
12:18 -> 4:6 - > <u>2:3</u>
Now let's check it against all the options:
A) 20:30 -> 2:3 and 2:3 = 2:3
Not our answer as it is congruent (equal too, the same as, etc)
B) We can see that the first number is larger than the second number, so without doing too much math we can see this is our answer!
42:28
(it simplifes to 6:4 -> 3:2)
(we do not have to do the following as we already have an answer, but here is the math)
C) 4:6
4:6 ->
2:3 = 2:3
D) 2:3
2:3 = 2:3